Is Dogecoin a blockchain protocol or cryptocurrency that's on an already existing blockchain network?
I know that Dogecoin is based of Luckycoin which in turn is based of Litecoin.
Dogecoins can be released through mining, much like Bitcoins, Ethereum, Litecions that have their own blockchain protocols.
We can say it's both. Dogecoin is a cryptocurrency who run in his own blockchain.
As you can see in this site doge coin have his own chain
https://dogechain.info/ and if you want to use it as a currency you can use a doge online wallet, or download the doge core from
https://dogecoin.com/Doge, LTC, ETH are a criptocurrency who born from the bitcoin core with some modifications, but each one have their own blockchain.